Thermomigrationfast azo dyes

ABSTRACT

Azo dyes of the formulawherein the substituents are each as defined in the description, are useful for dyeing and printing synthetic textile materials.

This invention relates to azo dyes of the formula

wherein

D is aryl or hetaryl other than 2,4-dinitro-6-ethanesulphonylphenyl,

A is —CO— or —SO—,

B is optionally substituted C₁-C₄-alkyl,

R¹ and R² are independently optionally OH— or C₁-C₄-alkoxy-substituted C₁-C₄-alkyl, and

R³ and R⁴ are independently H or CH₃,

with the proviso that A is SO₂ when D is a 6-nitrobenzothiazolyl radical.

Useful substituents for the optionally substituted C₁-C₄-alkyl B are Cl, C₁-C₄-alkoxy, C₁-C₄-acyloxy, CO₂-C₁-C₄-alkyl.

Suitable aryls D are substituted benzene derivatives of the formula (II)

wherein

X¹ and X⁵ are independently H, F, Cl, Br, —NO₂, —CN, —SO₂—B, —CO₂—B, —OH, —CHO or —CO—B,

X² and X⁴ are independently H, Cl, Br, NO₂ or B,

X³ is H, Cl, Br, —NO₂, —CN, —SO₂—B, —CO₂—B, —CH═O or B, and

B is as defined above.

Preferred hetaryls D are thiazoles (IIIa), isothiazoles (IIIb), thiophenes (IIIc), thiadiazoles (IIId), benzothiazoles (IIIe) and benzisothiazoles (IIIf) of the following formulae:

wherein

X¹ to X⁵ are each as defined above,

X⁶ is H, B, Cl, Br, —SB or —SO₂B,

X⁷ is CN, —CO₂B or —CO—B, and

B is as defined above.

Preference is given to dyes of the formula (I) wherein

D is a radical of the formula

wherein

X¹ and X⁵ are independently H, Cl, Br, CN, —NO₂, —SO₂—B or CO₂—B,

X² and X⁴ are independently H, B, Cl or Br,

X³ is H, B, Cl, Br, —NO₂, CN, —CO₂—B or —CH═O,

X⁷ is —CN, —CO₂—B, —CO—B, and

B is as defined above.

Particular preference is given to dyes of the formula (I) wherein

D is a radical of the formula

wherein

X¹ is H, Cl, Br, CN or NO₂,

X³ is H, CH₃, Cl, Br or NO₂,

X⁵ is H, Cl, Br or CN,

A is —SO—,

B is optionally Cl-substituted C₁-C₄-alkyl, especially methyl,

R¹ and R² are each C₁-C₄-alkyl, especially methyl, and

R³ and R⁴ are each hydrogen.

The dyes (I) are prepared by generally customary methods. For example, diazo components of the formula

D—NH₂  (VI)

wherein

D is as defined above,

are diazotized and coupled onto coupling components of the formula

wherein

A, B, R¹, R², R³ and R⁴ are each as defined above.

The diazotization is effected in the usual manner at −20 to 20° C. with the aid of alkali metal nitrites, nitrosylsulphuric acid or esters of nitrous acid in mineral acids (HCl, H₂SO₄, H₃PO₄) or lower fatty acids (acetic and/or propionic acid). The coupling is likewise carried out by customary methods, preferably by adding the aqueous solution or dispersion or aqueous/alcoholic solution to the diazonium salt solution and, if appropriate, adjusting the reaction mixture to pH 5-7 by addition of alkali.

A preferred process for preparing inventive 2,6-dicyanoazo dyes of the formula

wherein

R¹ to R⁴, A, B and X² to X⁴ are each as defined above,

is characterized in that conventionally prepared azo compounds of the formula

wherein

R¹ to R⁴, A, B and X² to X⁴ are each as defined above, and

Hal is halogen, preferably Cl or Br,

have their halogen atoms exchanged for cyano groups.

This exchange reaction is likewise known per se and described for example in the following patent literature: DE-A 1 544 563=GB 1 125 683; DE-A 2 456 495=GB 1 479 085; DE-A 2 759 103=GB 2 012 799; DE-A 2 846 439=GB 2 034 736; DD 2 17 232 (especially the references cited therein).

Thereafter, the o,o′-dihaloazo compound is reacted with metal cyanides or cyanide ion donor compounds in a polar organic solvent or water at temperatures of 50 to 150° C. until the halogen atoms are virtually completely replaced, which is readily monitorable by reference to thin layer chromatograms.

Suitable cyanides are in particular CuCN and Zn(CN)₂ and complex cyanides of the formula Me^(⊕) _(n)(CuCN)_(n+1) (Me=Na, K; n=1-3). Suitable cyanide ion former systems are for example fornaldroxime, cyanohydrins, nitroalkanes or formamide.

Preferred organic solvents are polar aprotic compounds such as, for example, DMF, DMSO, pyridine, N-methylpyrrolidone, chlorobenzene, dichlorobenzenes, etc.

A particularly suitable and preferred way of carrying out the halogen/cyano exchange is by means of a mixture of copper(I) cyanide and zinc cyanide.

Whereas the diazo components are generally known, only the precursors are known of the coupling components, cf. for example EP 313 918 or U.S. Pat. No. 5,194,598.

However, these compounds are readily obtained in a manner known per se, for example by reacting compounds of the formula

wherein

R¹ to R⁴ are each as defined above,

with

a) acid anhydrides, for example of the formula

wherein

B is as defined above, or

b) acid chlorides of the formula

B—A—Cl,

wherein

B and A are each as defined above.

The coupling components of the formula (VII) wherein B, R¹, R², R³ and R⁴ are each as defined under the formula (I) and A is SO₂ are new and likewise form part of the subject-matter of the present invention.

These acylations are preferably carried out in organic, preferably anhydrous, solvents. Water/organic solvent two-phase systems are also suitable.

Examples of suitable solvents are apolar organic solvents such as chlorinated hydrocarbons, for example methylene chloride, carbon tetrachloride, aromatic solvents, for example toluene, xylenes, chlorobenzene, dichlorobenzene, nitrobenzene, but also polar solvents such as acetone, dimethylformamide, N-methylpyrrolidone, sulpholane, etc.

It may be advantageous to use organic or inorganic bases to scavenge the hydrogen chloride formed.

Examples of suitable bases are sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, sodium bicarbonate, potassium bicarbonate, sodium hydrogenphosphate, sodium acetate and also amines such as, for example, trialkylamines, pyridine, dialkylaminopyridine, quinoline, dialkylanilines, etc.

The dyes of the invention, as is customary for disperse dyes, are virtually insoluble in water. They are particularly useful for dyeing and printing synthetic textile materials, especially textile materials composed of secondary cellulose acetate and cellulose triacetate, polyamide, for example polyhexamethyleneadipamide, and most suitably aromatic polyester, for example polyethylene terephthalate, by the dyeing and printing methods customary for these fibre varieties using aqueous or non-aqueous liquors or print pastes.

The dyes may lastly also be applied to synthetic textile materials by thermal transfer printing.

The dyes are further useful for thermal transfer printing on synthetic recording materials in optical recording processes, for example for printing polyester-coated paper.

The scarlet to blue dyeings on polyester obtained with the new dyes combine good all round fastnesses with high colour strength, bright hues and, in particular, excellent thermomigrationfastness.

Compared with the closest known dyes of JP-A 47 25 487, which have a 6-nitrobenzothiazole diazo component, and JP-A 4725488, which have a 2,4-dinitro-6-ethylsulphonylphenyl diazo component, the new dyes have superior fastness properties.

EXAMPLES Example 1

Preparation of the dye of the formula

To a solution of 7.3 g of 2-cyano-4-nitroaniline in 30 ml of propionic acid and 60 ml of glacial acetic acid were added dropwise over 30 minutes at 0 to 5° C. 8.3 ml of a 42 per cent strength nitrosylsulphuric acid solution in sulphuric acid with stirring. The mixture was subsequently stirred at 0° C. for two hours.

The above diazotization mixture was gradually added at 0° C. to a solution of 16.4 g of β-alanine N-(3-methoxy-3-oxopropyl)-N-[3-[(methanesulphonyl)oxy]phenyl]-methyl ester and 2 g of amidosulphonic acid in 200 ml of methanol, ice-water being added to make up to a volume of 1500 ml. Overnight stirring was followed by suction filtration and washing until neutral. Yield: 19.9 g. The crude product was recrystallizable from DMF.

λ_(max): 503 nm (CH₂Cl₂)

The dye dyes polyester in a bluish red having good fastnesses, especially very good thermomigrationfastness.

The coupling component needed is obtainable by reacting β-alanine N-(3-methoxy-3-oxopropyl)-N-[3-[oxy]phenyl]-methyl ester with methanesulphonyl chloride in toluene at 70° C. in the presence of triethylamine.

Analogous or similar methods provide the dyes of the formula

reported in the tables hereinbelow, dyes where A═SO₂ being described in Table 1 and dyes where A═CO in Table 2.

TABLE 1 Ex. Hue on λ_(max) nm No. D B R¹ polyester (CH₂Cl₂) 2

CH₃ CH₃ yellowish scarlet 472 3

CH₃ C₂H₅ bluish red 507 4

C₂H₅ CH₃ bluish red 502 5

C₄H₉ CH₃ bluish red 503 6

CH₂Cl CH₃ red 502 7

CH₃ CH₃ bluish red 513 8

CH₃ CH₃ reddish violet 542 9

CH₂Cl CH₃ bordeaux 511

TABLE 2 Ex. Hue on λ_(max) nm No. D B R¹ polyester (CH₂Cl₂) 10

CH₃ CH₃ bluish red 509 11

C₂H₅ CH₃ bluish red 510 12

C₃H₇ CH₃ bluish red 510 13

CH₃ CH₃ yellowish red 496 14

CH₃ CH₃ bluish red 511 15

CH₃ CH₃ ruby 514 16

CH₃ CH₃ reddish blue 568 17

C₂H₅ CH₃ reddish blue 570 18

CH₃ CH₃ reddish violet 542 

What is claimed is:
 1. A dye of the formula:

wherein D is hetaryl or a radical of the formula (II)

wherein X¹ and X⁵ are independently is H, F, Cl, Br, —NO₂, —CN, —CO₂B, —OH, —CHO or —CO—B, X² and X⁴ are independently H, Cl, Br, NO₂, or B, X³ is H, Cl, Br, —NO₂, —CN, —SO₂B, —CO₂B, B or —CH═O, A is —CO— or —SO₂—, B is optionally substituted C₁-C₄-alkyl, R¹ and R² are independently optionally OH— or C₁-C₄-alkoxy-substituted C₁-C₄-alkyl, and R³ and R⁴ are independently H or CH₃, with the proviso that A is SO₂ when D is a 6-nitrobenzothiazolyl radical.
 2. A dye of the formula:

wherein D is a radical of the formulae (IIIa) to (IIIf)

wherein X¹ to X⁵ are independently H, F, Cl, Br, —NO₂, —CN, —SO₂—B, —CO₂—B, —OH, —CHO or —CO—B, X⁶ is H, B, Cl, Br, —SB or —SO₂B, X⁷ is CN, —CO₂B or —CO—B, and B is optionally swbstituted C₁-C₄-alkyl.
 3. The dye according to claim 1, wherein D is a radical of the formula

wherein X¹ and X⁵ are independently H, Cl, Br, CN, —NO₂, or CO₂—B, X² and X⁴ are independently H, B, Cl or Br, X³ is H, B, Cl, Br, —NO₂, CN, —CO₂—B or —CH═O, X⁷ is —CN, —CO₂—B or —CO—B, and B is optionally substituted C₁-C₄-alkyl.
 4. The dye according to claim 1, wherein D is a radical of the formula

wherein X¹ is H, Cl, Br, CN or NO₂, X³ is H, CH₃, Cl, Br or NO₂, X⁵ is H, Cl, Br or CN, A is —SO₂—, B is optionally Cl-substituted C₁-C₄-alkyl, R¹ and R² are each C₁-C₄-alkyl, and R³ and R⁴ are each hydrogen.
 5. A dye according to claim 1 of the formula

wherein X¹ is H, Cl, Br, CN or NO₂, X³ is H, CH₃, Cl, Br or NO₂, and X⁵ is H, Cl, Br or CN.
 6. Process for preparing the dye according to claim 1, which comprises diazotizing diazo components of the formula D—NH₂  (VI) wherein D is as defined in claim 1, and coupling onto coupling components of the formula

wherein A, B, R¹, R², R³ and R⁴ are each as defined in claim
 1. 7. A compound of the formula

wherein B is optionally substituted C₁-C₁-alkyl, R¹ and R² are independently optionally OH— or C₁-C₄-alkoxy-substituted C₁-C₄ alkyl, R³ and R⁴ are independently H or CH₃, and A is SO₂.
 8. The dye as claimed in claim 4, wherein B is optionally Cl-substituted methyl and R¹ and R² are methyl.
 9. A dye of the formula:

wherein D is hetaryl or a radical of the formula (II)

wherein X¹ and X⁵ are independently is H, F, Cl, Br, —NO₂, —CN, —CO₂B, —OH, —CHO or —CO—B, X² and X⁴ are independently H, Cl, Br, NO₂ or B, X³ is H, Cl, Br, —NO₂, —CN, —CO₂B, B or —CH═O, A is —CO— or —SO₂—, B is optionally substituted C₁-C₄-alkyl, R¹ and R² are independently optionally OH— or C₁-C₄-alkoxy-substituted C₁-C₄-alkyl, and R³ and R⁴are independently H or CH₃, with the proviso that A is SO₂ when D is a 6-nitrobenzothiazolyl radical.
 10. A process for dyeing or printing synthetic textile materials which comprises applying the dyes according to claim 1 to said material.
 11. The process according to claim 10, wherein said material is secondary cellulose acetate, cellulose triacetate, polyamide or aromatic polyester.
 12. A process for producing an optical recording material which comprises thermal transfer printing of the dye according to claim 1 on a synthetic recording material.
 13. A process for printing on synthetic textile materials which comprises thermal transfer printing of the dye according to claim 1 on said synthetic textile material.
 14. The process as claimed in claim 6, wherein said diazotizing is carried out at −20 to 20° C. with the aid of an alkali metal nitrite, nitrosylsulphuric acid or an ester of nitrous acid in mineral acid or lower fatty acid. 